This map depicts US Poverty and Political Leanings by counties. It does this by creating a FeatureLayer instance from an existing portal item and adds it to a basic Map in a SceneView. When an item is loaded as a layer, the Renderer and PopupTemplate saved to the layer in the portal are preserved in the application.
To load a layer from a portal, you must use its portal ID.
// Creates a layer from a Portal layer item id
Layer.fromPortalItem({
portalItem: {
id: "af1ad38816814b7eba3fe74a3b84412d"
}
}).then((layer) => {
// Adds layer to the map
map.add(layer);
});
The renderer of the layer in this app uses several visual variables, that were set in the ArcGIS Online Map Viewer and saved to the layer. So there is no need to set a custom renderer in code.
Please refer to the ArcGIS Organization portals for information on how the ArcGIS Maps SDK for JavaScript makes use of working with portal items.